Support generic dialect

Author: alamb

src/parser/mod.rs

@@ -6274,7 +6274,7 @@ impl<'a> Parser<'a> {
             self.expect_keyword(Keyword::WITH)?;
             let table_name = self.parse_object_name(false)?;
             AlterTableOperation::SwapWith { table_name }
-        } else if dialect_of!(self is PostgreSqlDialect)
+        } else if dialect_of!(self is PostgreSqlDialect | GenericDialect)
             && self.parse_keywords(&[Keyword::OWNER, Keyword::TO])
         {
             let next_token = self.next_token();

tests/sqlparser_postgres.rs

@@ -765,7 +765,7 @@ fn parse_alter_table_owner_to() {
     ];
 
     for case in test_cases {
-        match pg().verified_stmt(case.sql) {
+        match pg_and_generic().verified_stmt(case.sql) {
             Statement::AlterTable {
                 name,
                 if_exists: _,